The use of power tools, especially cordless power tools, has increased dramatically in recent years. Cordless power tools provide the ease of a power assisted tool with the convenience of cordless operation. Conventionally, cordless power tools have been driven by permanent magnet (PM) brushed motors that receive DC power from a battery assembly or converted AC power. In other cordless power tools, a brushless DC motor is used, which achieves commutation electronically by controlling the flow of current to the stator windings. Other types of motors used in power tools include AC motors and universal (AC/DC) motors. Power delivery to motors is generally controlled by various types of electronics control modules.
Motors and electronics control modules in a power tool generate a considerable amount of heat. A fan is typically coupled to the output shaft of the motor to cool the motor and electronics control module. Air inlets and outlets are provided in various parts of the power tool housing to help direct cooling air through or over the motor and electronics control module, and out of the air outlets. The present invention improves on the existing cooling designs in power tools to more efficiently cool the motor and the electronics control module.